<%
String bookname=request.getParameter("bookname");
String num="",bname="",aut="",pri="",pub="";
ConnDB conn=new ConnDB();%>
<table width="100" border="1">
<tr>
<th scope="col"> </th>
<th scope="col"> </th>
<th scope="col"> </th>
<th scope="col"> </th>
<th scope="col"> </th>
</tr>
<%
String sql="select * form BOOK where BOOKNAME='"+bookname+"'";
ResultSet rs=conn.doQuery(sql);
while(rs.next())
{num=rs.getString(1);
bname=rs.getString(2);
aut=rs.getString(3);
pri=rs.getString(4);
pub=rs.getString(5);
%>
<tr>
<td><%=num%></td>
<td><%=bname%></td>
<td><%=aut%></td>
<td><%=pri%></td>
<td><%=pub%></td>
</tr>
</table>
<% } %>
</body>
</html>
String bookname=request.getParameter("bookname");
String num="",bname="",aut="",pri="",pub="";
ConnDB conn=new ConnDB();%>
<table width="100" border="1">
<tr>
<th scope="col"> </th>
<th scope="col"> </th>
<th scope="col"> </th>
<th scope="col"> </th>
<th scope="col"> </th>
</tr>
<%
String sql="select * form BOOK where BOOKNAME='"+bookname+"'";
ResultSet rs=conn.doQuery(sql);
while(rs.next())
{num=rs.getString(1);
bname=rs.getString(2);
aut=rs.getString(3);
pri=rs.getString(4);
pub=rs.getString(5);
%>
<tr>
<td><%=num%></td>
<td><%=bname%></td>
<td><%=aut%></td>
<td><%=pri%></td>
<td><%=pub%></td>
</tr>
</table>
<% } %>
</body>
</html>
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28: ResultSet rs=conn.doQuery(sql);
29:
30: while(rs.next())
31: {num=rs.getString(1);
32: bname=rs.getString(2);
33: aut=rs.getString(3);
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause java.lang.NullPointerException
org.apache.jsp.query_jsp._jspService(query_jsp.java:86)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.26 logs.
空指针啊,
query.jsp at line 30
while(rs.next())所以肯定是rs为空了。
也就是这句没有将rs实例化
ResultSet rs=conn.doQuery(sql);
断点调试下啊。、首先看你的conn是否正确链接到数据库了。你的sql语句是否能够正确执行呃。。
确认你的doQuery是正确的
应该是 from ,要细心奥
7楼够细心的。。